Method and apparatus for registration of location information of wireless devices in a wireless communication network supporting multicast calls

Abstract

An apparatus and method for transmitting push-to-talk (PTT) communications through multicast channels to a plurality of wireless devices. The PTT server uses the unicast approach to deliver the PTT communication to a group of PTT clients when it does not have the location information of the PTT clients in the group. In one embodiment, the wireless devices report their location to a PTT server after receiving a PTT communication for a group and a timer is started. The wireless devices continue to report their location when moving from an area served by one base station to an area served by another before the timer expires. The PTT server also starts the timer for that PTT group with the same value after initiating the PTT group communication. The PTT server uses the location information to determine if multicast channels can be used when transmitting PTT communications to the wireless devices.

What is claimed is: 
     
       1. A method for transmitting location information of a wireless communication device comprising:
 receiving, at the wireless communication device from a base station, a push-to-talk (PTT) communication; 
 starting or resetting, by the wireless communication device, a timer upon receiving the PTT communication; 
 determining, by the wireless communication device, that the PTT communication is a group call; 
 in response to the determining that the PTT communication is a group call, transmitting, by the wireless communication device, the location information of the wireless communication device to a PTT server; 
 comparing, by the wireless communication device, a newly received location information of the wireless communication device with a stored location information of the wireless communication device; and 
 in response to determining that the newly received location information differs from the stored location information, sending, by the wireless communication device, the newly received location information to the PTT server while the timer is still running. 
 
     
     
       2. The method of  claim 1 , further comprising:
 monitoring location information broadcast from the base station; and 
 storing the monitored location information. 
 
     
     
       3. The method of  claim 1 , wherein the location information is an identification of the base station. 
     
     
       4. The method of  claim 1 , wherein the location information is an identification of a multicast region. 
     
     
       5. The method of  claim 1 , wherein transmitting the location information comprises sending a registration message with the location information to the PTT server. 
     
     
       6. A non-transitory computer-readable medium comprising at least one instruction, which, when executed by a machine, causes the machine to perform operations, the at least one instruction comprising:
 a set of instructions to cause a wireless communication device to receive from a base station a push-to-talk (PTT) communication; 
 a set of instructions to cause the wireless communication device to start a timer; 
 a set of instructions to cause the wireless communication device to determine that the PTT communication is a group call; 
 a set of instructions to cause the wireless communication device to transmit location information of the wireless communication device to a PTT server, in response to the determination that the PTT communication is a group call; 
 a set of instructions to cause the wireless communication device to compare a newly received location information of the wireless communication device with a stored location information of the wireless communication device; and 
 a set of instructions to cause the wireless communication device to send the newly received location information to the PTT server while the timer is still running in response to a determination that the newly received location information differs from the stored location information. 
 
     
     
       7. The non-transitory computer-readable medium of  claim 6 , further comprising:
 a set of instructions to monitor location information broadcast from the base station; and 
 a set of instructions to store the monitored location information. 
 
     
     
       8. The non-transitory computer-readable medium of  claim 6 , wherein the location information is an identification of the base station. 
     
     
       9. The non-transitory computer-readable medium of  claim 6 , wherein the set of instructions to cause the wireless communication device to transmit the location information comprises a set of instructions to cause the wireless communication device to send a registration message with the location information during transmission to the PTT server. 
     
     
       10. An apparatus for transmitting location information of a wireless communication device comprising:
 a communication means for receiving, at the wireless communication device, from a base station a push-to-talk (PTT) communication; and 
 a processing means for:
 starting a timer upon receiving the PTT communication; and 
 determining, by the wireless communication device, that the PTT communication is a group call; 
 
 wherein the communication means is further for transmitting the location information of the wireless communication device to a PTT server in response to the determination that the PTT communication is a group call, 
 wherein the processing means is further for comparing a newly received location information of the wireless communication device with a stored location information of the wireless communication device, and 
 wherein the communication means is further for sending the newly received location information to the PTT server while the timer is still running in response to a determination that the newly received location information differs from the stored location information. 
 
     
     
       11. The apparatus of  claim 10 , wherein the processing means is further for:
 monitoring location information broadcast from the base station; and 
 storing the monitored location information. 
 
     
     
       12. The apparatus of  claim 10 , wherein the location information is an identification of the base station. 
     
     
       13. The apparatus of  claim 10 , wherein the location information is an identification of a multicast region. 
     
     
       14. The apparatus of  claim 10 , wherein the communication means being for transmitting the location information comprises the communication means being for sending a registration message with the location information to the PTT server.